Echocardiographic techniques are extremely useful in the evaluation of left ventricular function. M-mode and two-dimensional echocardiography have been extensively used. However, these techniques do not give information on blood flow parameters which have been shown using invasive methods to give much information about left ventricular function. Pulse Doppler echocardiography, a new, easily performed non-invasive technique can be used to measure the velocity flow profiles in the heart and great vessels. The overall objective of this project is to develop and extend the usefulness of pulse Doppler techniques in the study of systolic and diastolic function of the left ventricle. The specific aims are: (1) Further validation and quantification of pulse echo Doppler techniques in the experimental animal and in human subjects. (2) Development of additional technological improvements so as to extend the usefulness of the technique. (3) The study of pulse Doppler echo in patients in health and disease. We shall define the normal values for various left ventricular performance parameters and study the effects of various arrhythmias on these parameters and study abnormalities at rest or during stressful interventions in patients with left ventricular hypertrophy, or coronary artery disease. The studies should allow us a greater understanding of the effects of disease on left ventricular systolic and diastolic function and develop as a clinical tool this technique for the evaluation of left ventricular function in patients with heart disease.